Selective system for gunfire control



Nov. 5, 1946. A. P. DAVIS vrs1-Al. l

` SELECTI'VE SYSTEM FOR GUNFIRE CONTROL 4 sheets-sheet 1 Filed April 27,1957 NMR Nov. 5r, 1946. A. P. DAvls E-rAL 2,410,638

l sELETIvE SYSTEM FOR GUNFIRE CONTROL Filed April. 27', 1957 4sheets-.sheet 2 Pira/1 Roz/ -FaL/.aw UP FOLLOW uP Jaune; lf. Mal'omer 75Mv@ ylamn-Arrols Nov. 5, 1946. A. P. DAvvls ETAL SELECTIVE SYSTEM FORGFIRE CONTROL 4 Sheets-Sheet 3 Filed April 27, 1957 Img moss-Lem /mkefrBEAR/Ns L55 Nv.'5,1946 A'. P. vis- ETAF 2,410,633

SELECTIVE SYSTEM FOR GUNFIRE CONTROL Patented Nov. 5, 17946 "S ES FICESELECTVE SYSTEM FOR GUNFIRE CONTROL York Application April 27, 1937,Serial No. 139,146

Claims.

This invention relates to gun re control systems and has particularreference to a system for controlling the firing of the main or othergun batteries on a ship at any selected point in the ships motion inroll or pitch.

Range elevation and sight deflection are ordinarily computed withreference to a horizontal plane, so that the position of the guns iscorrect for firing only at the instant that the deck of the ship is in atrue horizontal plane, i. e., at the midpoint of the roll or pitch.Accordingly, correction is required for so-called trunnion-tilt, i. e.,the displacement from the horizontal caused by the motion of the shipabout the line of sight, or cross-level angle, and correction must alsobe made for motionl of the ship in the plane of sight, or level angle.The roll and pitch angles, as measured by a stable element, such as agyroscopic vertical, must be first lconverted into crosslevel and levelangles, asv determined by relative target bearing.

In the systemof the present invention, range elevation is automaticallycorrected for trunnion-tilt and combined with director correction orlevel angle to generate the gun elevation order, which indicates thecorrected elevation at any instant so that the guns may be continuouslycorrected in elevation. The sight deflection is automatically correctedfor trunnion-tlt and combined with relative target bearing to generatethe gun train order, which indicates the correction at any instant sothat the guns may be continuously corrected in train.

Also in accordance with the present invention,

means are provided for introducing the angular correction to rangeelevation in order that the guns may be fired the maximum number oftimes in `either level or cross-level, this correction being introducedeither as director correction or cross-level set. Furthermore, automaticmeans are provided whereby ring of the gun can be effected at theselected point in either level or cross-level with a high and consistentdegree of accuracy, independently of the variable reaction rates ofindividual operators.

More particularly, the fire control system of this invention essentiallycomprises a stable element, preferably a gyroscopic vertical withassociated means for measuring and transmitting the angle of roll andpitch of Vthe ship, mechanical means for converting these angles intolevel and cross-level angles relative to the bearing of the target,mechanical means for correcting range elevation and sight deflection fortrunnion-tilt in accordance with cross-level or cross-level set,

a dilerential for combining the corrected range elevation with directorcorrection or with level for gun elevation order, a differential forcombining the corrected sight deiiection with the relative targetbearing for gun train order, automatic means for firing in accordancewith these corrected and selected values, and switching means forselectively preparing the automatic ring means in accordance with iiringprocedure.

For a more complete understanding of this invention, reference `may .behad to the accompanying drawings, in which:

Figure 1 is a schematic mechanical diagram of the selective gun iirecontrol system of this invention;

Fig. 2 is a schematic illustration of the stable element and a portionof the electric follow-up of the system;

Fig. 3 illustrates partially in perspective and partially schematically,the roll and pitch converter; and l Fig. 4 illustrates, partially inperspective and partially schematically, the trunnion-tilt co1'-`rector.

Referring'to Fig. 2 of the drawings, the stable element designated lI0in Fig. 1, preferably comprises a gyroscopic vertical, including thegyroscope I I, universally mounted on the gimbal support I2 having thenormally vertical shaft i3 journalled in follow-up support i 4 andconstantly rotated by motor I5 carried by follow-up support I4. A bailI6 xed on the support I4 extends over the gyroscope II and carries therespective pitch and roll follow-up coils I'I and I8, which arepositioned to be inductively energized by the electro-magnet I3 mountedon the gyroscope II as the latter tilts relatively to the support I4.

The pitch follow-up coil Il is part of the follow-up system 20 forenergizing the motor 2| in response to relative movement of thegyroscope II to drive the support I4, by means of shaft 32 and toothedsector 30, which is secured to arm 3i of support I4 at right angles tothe pitch axis, so that support I4 follows the Imovement of the ship inpitch and maintains the coil I1 in coincidence or alignment with theelectro-magnet I 9. Similarly, the roll follow-up coil I8 is part of thefollow-up system 22 for energizing the motor 23 to drive the outergimbal ring 26, by means oi gears 21, worm 26, and toothed sector 25,which is secured to outer gimbal ring 24, so as to maintain coil I8 inalignment with the electro-magnet I9. n Further details of the follow-upmechanism, which form no part of the present invention, are

3 illustrated and described in copending application Serial No. 53,736,filed December 10, 1,935.

With the follow-up support I4 being stabilized in this manner, thedegree of motion of the ship in pitch and roll is represented by theproportional movements of the follow-up systems 20 and 22. Accordingly,the angular'motion in roll is measured and transmitted by roll outputshaft 28. The angular motion in pitch is measured and transmitted, plusa function of the roll angle, to pitch and roll output shaft 29.

As is illustrated schematically in Fig. 1, th outputs of shafts 28 and29of stable element I9 are introduced into roll and pitch converter 34,to be described, which also receives relative target bearing throughshaft 35 driven by motor 36 actuated by a conventional type ofvfollow-up 31 driven by high and low speed self-synchronizingv motors38, which receive target bearing electrically from a suitablecontrolling director, not shown, and forming no part of the presentinvention. Hand crank 39 may be clutched to shaft 35 for manualfollow-up, if desired. In the roll and pitch converter 34, illustratedin detail in Fig. 3, the target bearing shaft 35 is connected -by bevelgears 4|) to shaft 4I having pinion 42 driving gear 43 secured to theend of hollow shaft 44 journalled in hub 45 of main frame support 46secured to the deck of the ship The upper end of hollow shaft 44 is ttedwith supporting arms 41, 48 and 49, which accordingly move with changein target bearing, Arm 41 carries one pivot 58 of roll ring 5|, Whoseopposite pivot 52 is hollow and journalled in arm 49.

Roll angle shaft 28 is connected, in the roll and pitch converter 34,through bevel gear 53 to one gear 54 of the differential 55, the othergear 56 of which meshes with pinion 51 on relative target bearing shaft35. R011 angle with relative target bearing thus added by differential55 is transmitted by shaft 58 and bevel gears 59 to hollow shaft 60journalled in shaft 44 and having at its upper end the gear 6I meshingwith gear 62 xed on shaft 63 journalled in arm 48 and having a pinion 84meshing with rack 65 l on roll ring I. The addition of relative targetbearing to roll angle by differential 55 is to prevent displacement ofroll ring 5I by relative rotation of gear 62 when target bearing inputshaft 44 is trained through relative target bearing. Gearing 66transmits roll angle t0 indicating dial 61.

The pitch and roll shaft 29 is connected by gear 68 to gear 69 ofdifferential 19, which also receives roll from shaft 28 through gears 1I, shaft 12, worm gears 'I3 and shaft 14. The differential subtracts theroll factor so that pitch angle is directly indicated by pitch dialdriven by differential 18 through gears 16.

Pitch and roll shaft 29 is connected by gears 11 to one side ofydifferential 18, the other side of which is connected by gears 19 torelative target bearing 'shaft 35. Relative target bearing is thus addedto pitch and roll angle by differential 18, whose output shaft 89 drivespitch input shaftJ 8| through gears 82. Pitch input shaft 8l isjournalled in roll input shaft 69 and its upper end carries gear 83driving gear 84 on shaft 85 journalled in arm'49 and hollow pivot 52 ofroll ring 5I. The shaft 85 carries the pinion 86 meshing with rack 81 onpitch ring 88, which is pivotally mounted in spaced relation to rollring 5I on pivots 89 located 90 from pivots 50 and 52. Relative targetbearing, is Yadded in this way vby differential 18 to preventdisplacement of pitch ring 88 by relative rotation of gear 84 whentarget bearing input shaft 44 is trained through relative targetbearing. Also, the factor of roll added to pitch by the stable elementI0 prevents the motion of the roll ring 5I from affecting the positionof the pitch ring 88 when pitch input shaft 8| is locked.

Integral with pitch ring 88 are four equally spaced arms 99 convergingto a conical shaft 9| normally coaxial with pitch input shaft 8|.Fitting over conical shaft 9| is a hollow shaft 92 centrally supportedby four equally spaced arms 93 of cross level ring 94 positioned inspaced relation to pitch ring 88 and so supported by shafts 9| and 92 asto follow the motion of pitch ring 88. Cross level ringI 94 is providedwith pivot pins 95, spaced 180 apart, in which the outer or level ring96 is pivoted, in spaced relation to cross level ring 94. Level ring 96is in turn provided with hollow pivot 91 and opposite pivot pin 98spaced 90 from pivots 95 and journ'alled in respective brackets 99 and|89 of main support frame 46.

The cross leve]` ring 94 carries rack IBI engaging pinion |92 mounted onshaft |93 journalled in hollow pivot 91 of outer or level ring 96 andhaving the gear |84 at its outer end which meshes with pinion |95 oncounter-shaft |66 journalled in bracket |61 of outer or level ring 96.This counter-shaft |06 is provided in order that relative motionIbetween rings 94 and 961s not imparted to cross-level output shaft |08journalled' in bracket 99 colinearly with shaft |93 and -driven by thecounter-shaft I 66 by gears |89, Thus, shaft |98 mechanically transmitscross-level angle. converted from roll, pitch and relative targetbearing The outer or level ring 96 carries rack IIB,

spaced from pivots 91 and 98, which meshes with pinion III mounted onlevelY output shaft II2 journalled in a bracket I I3 mounted 0n mainframe 46. Thus shaft I I2 mechanically transmits level angle,converted-from roll, `pitch and rela'- tive target bearing. v l

It will be seen that the roll and pitch converter 34 comprises two setsof mountings which are free to rotate with respect to each other about acommon vertical axis. Each set, level and cross level, roll and pitch,comprises two rings each, 96 and 94, 5I and 88, respectively, pivoted atright angles to each other. One ring of each set 96 (level) and 5I(roll) vis pivoted about an axis fixed with respect to the deck whilethe second. ring of each set 94 (cross-level) and 88 .(pitch) is mountedon the corresponding firstv ring 96 (level) and 5I (roll), respectively,so that it can be maintained in a horizontal plane. The outer set ofrings 96 (level) and 94 (cross-level) is rotatably mounted with respectto the main frame 46 and the deck of theuship, whereas the inner set ofrings 5|' (roll) v and 88 (pitch) is rotated, i. e. trained throughrelative target bearing, by nieans'of support arms 41, 48 and 49 whenshaft 44 carrying them is trained through relative target bearing bytarget bearing shaft 35.

Actually the roll Yand pitchY axes are fixed with respect to the deckand the level andy cross-level axes are trained. However, in order tosimplify construction, the level and A cross-level axesfare made fixedand the roll and pitch axes are rotated through relative target bearing,but in the opposite direction to maintain therelative position of thetwo sets of axes. I

As is illustrated in Fig. 1,-cross-'level angle is mechanicallytransmitted by shaft |08 to dial H3, calibrated to indicate generatedcross-level angle; also to a conventional form of follow-up H4, such asthe contact type; also to ring delay compensator H5, to be described,and thus to automatic ring contacts H6 thereof; and also to mechanicaldifferential ||1. The other side of differential ||1 also receivescross-level angle, either from follow-up l |4 through shafts ||8 and H9,or cross-level set introduced manually by hand-crank |26 clutched bygears |2| to shaft H9. Dial |22 is geared `to hand crank |20 andindicates cross-level set. Follow-up H4 through its follow-up motor |23and shafts H8 and |24 transmits cross-level angle to trunnion-tiltcorrector |25. Cross-level set from hand crank mayalso be used tointroduce cross-level angle to the trunnion-tilt corrector |25 throughshafts ||8and` |24. Hand crank |26, gears |21, and shaft |28 areprovided for manual follow-up.

Range elevation 'is introduced into trunniontilt corrector |25 byhand-crank |29, gears |30 and'shaft |3| and is indicated on helicalscale |32 of range drum |33 by index pointer |34 threaded onl lead screw|35 driven by gears |36, which also .drive range drum |33, as crankhandle 29. is turned.

Sight deection is introduced into trunniontilt corrector |25 byhand-crank |31, gears |38 and shaft |39, and is indicated on dial drivenby gear |4| connected to one of the gears |38.

The trunnion-tilt corrector |25, illustrated in detail in Fig. 4,corrects the range elevation input from shaft |3| and the sight deectioninput from shaft |39 in termsof cross-level received from shaft |24, bymechanically Solving the following.: equations:

"Agus/17E sm'cL-td cos CL E=E cos CL-d sin CL Where Ace-corrected sightdeflection, Ec=cor rected range elevation, E=range elevation,positive-up; d=deflection, positive-to right, CL: cross level,positive-down at left, the directions be considered positive whenvlooking toward the target.

Referring to Fig. 4, in the trunnion-tilt corrector |25, the rangeelevation input shaft |3| is connected Iby universal joint |42 to oneend of shaft |43 connected at its other end by gears |44 to a parallelthreaded shaft |45 mounted on toothed disc |46, which is rotated throughcrosslevel angle by meshing worm |41 on cross-level input shaft |24, andwhose axis of rotation is the axis X--X, which coincides with the centerof the universal joint |42. A nut |48 threaded onshaft |45 moves alongshaft |45 as range input shaft |3| rotates it. The position of the nut|48 vertically below axis X-X, in the plane ofthe drawings, isproportional to E cos CL, While the position of nut horizontally fromaxis Ye-Y is proportional to E `sin CL. Axis Y-Y is the line of travelof nut |48 for zero cross-level and is a vertical axis intersecting axisX-X in a point corresponding to zero range elevation.

The sight deflection input shaft |39 is connected by a second universaljoint |49, positioned on the rear side of disc |46 and coinciding withaxis X-X, to 'one end of shaft |56, the other end of which is connectedby gears |5| to threaded shaft |52 mounted on the rear surface of disc|46. A nut |53 moves along shaft |52 when the latter is rotated by sightdeflection input shaft |39, and the position of-nut |53 along shaft |52vertically with respect to axis X--X is proportional 'to d cos CL. Theposition of nut |53- along shaft' |52 horizontally from axis Y-Y isproportional to d sin CL. Axis Z-Z is the line of travel ofnut |53 forzero cross-level andis a' vertical axis intersecting axis X-X in a pointCorresponding to zero sight deflection.

A lateral pin |54 on nut |48 fits slidably into a horizontal slot |55 ofslide |56, which is constrained by rollers |51 to move in a verticaldirection as the vertical component of movement of nut |48. Pin l |54 onnut |48 also ts slidably into a vertical slot |58 of slide |59, which isconstrained by rollers |60 to movement in a horizontal direction as thehorizontal component of movement of nut |48.

Similarly, a lateral pin |6| on nut |53 fits slidably into a horizontalslot |62 of slide |63, which is constrained by rollers |64 to move in avertical direction as nut |53 moves along shaft |52. Pin |6| also fitsinto vertical slot |65 of slide |66, which is constrained by rollers |61to move in a horizontal direction as nut |53 moves along shaft Thevertical displacement of slide |56 proportional to E cos CL istransmitted by rack |68 and meshing pinion |69 to one side of correctedrange elevation (Ec) differential |10, the other side of which isconnected by pinion |1| to rack |12 of horizontal slide |66 and receivesan input therefrom proportional to dsin CL. The resultant output ofdifferential |19 is the sum of these two inputs and is equal to E cosCL-d sin CL, which is the corrected range elevation, Ec. The output gear|13 of differential |10 is connected by gear |14 Vto corrected rangeelevation or Ec output shaft |15.

`The horizontal displacement of slide |59 proportional to E' sin CL istransmitted by rack |16 and meshing pinion |11 to one side of correctedsight deflection (At) differential |18, the other side of which isconnected by pinion |19 to rack |89 of vertical slide |63 and receivesan input therefrom proportional to d cos CL. The resultant output ofdifferential |18 is the addition of these two inputs and is equal to18/1'1 E sin CL-l-dcos CL which is the .corrected sight deflection, Ac.The output gear |8| of differential |18 is connected by gear |62 tocorrected sight deflection or Ac output shaft |83. The empirical factor18/1'1 is introduced by selecting pinion |11 to give the desired ratiobetween E sin CL input from rack |16 and the speed of differentialoutput gear |82.

Referring to Fig.` 1, the corrected sight deflection (Ae) output shaft|83 from the trunnion-tilt corrector |25 is geared to the rotors of highand low speed differential transmitters |84, preferably of theself-synchronizing type, the stators of which through connections |85electrically receive relative target bearing from the controllingdirector, not shown. The resultant electrical output, whichis gun trainorder Ot, is transmitted by connections |66 to any desired remote firingpoint, and is also transmitted to high and low speed electrical receivermotors |81, preferably of the self-synchronizing type, which driveindicating dials |88.

The corrected range elevation (Ec) output shaft |15 from trunnion-tiltcorrector |25 is connected to one `side of mechanical differential |89,to the other side of which is connected shaft introducing directorcorrection or level, from sources to be described. The resultant outputof differential |69, whichis gun elevation orderyOe, is

` transmitted by respective shafts |9| and |92 and suitable gearing tohigh and low speed indicating dials |93 and to the rotors of high and10W speed electrical transmitters I 94, preferably of theselfsynchronous type, from which the elevation order (Oe) may betransmitted to any desired firing point.

The aforementioned director correction applied to differential |89, isreceived electrically from the controlling director, not shown, by highand loW speed receiver motors |95, preferably of the selfsynchronizingtype, and transmitted mechanically to the contact follow-up |96, whichtransmits it by shafts |91, |98 and suitable'gearing to the input shaftI 90 of the differential |09. Handcrank |99 and gears 200 are providedon shaft |91 for manual follow-up.

The aforementioned alternative level input to differential |89 isreceived from level output shaft ||2 of roll and pitch converter 34.Shaft II2 is connected to level indicating dial 20 I, and to shaft 202,which is connected by shaft 293 and suitable gearing to level follow-up204, which is preferably of vthe contact type similar to cross-levelfollovvup 4. The follow-up motor 209 of follow-up 204 is connected byshafts 296 and 207 to input shaft |90 of differential |89. Hand-crank203 and gears 209 are connected to shaft 206 for manual follow-up.

Level is also transmitted from roll and pitch converter 34 by shafts ||2and 202 to firing delay compensator 2|0, to be described, for actuatinginner firing contact 2| I, Level is also transmitted by shaft 2 I2,geared to shaft 202, to one side of mechanical differential 2|3, theother side of which is locked, because when cross-level fire is in use,director correction follow-up |96 is inoperative, as Will be explained.Thus shaft 2|4 is driven by differential 2 I 3 through the level angleand, through its gear 2|5, drives the outer firing contact 2|6 ofautomatic ring device 2|1. Where director nre is employed, differential2|3 adds the input from level shafts 202 and 2 I2 and from directorcorrection shaft |91 and the output shaft 2| 4 and outer firing contact2I6 are driven accordingly.

The firing delay compensators ||5 and 2|0 automatically compensate forthe time delay between the closing of the firing switch and the passageof the projectile out of the gun, so that the gun is actually firedahead of the usual firing time. In the form shown, the compensator 2| 0essentially comprises a drag coupling interposed between the ends ofaligned shafts 202 and 2|8 leading to inner firing contact 2| I, theformer carrying electro-magnet 2|9 and the latter carrying a copper ring220. As the electro-magnet 2|9 is rotated by level shaft 202, eddycurrents induced in copper ring 220 cause it to follow the magnet 2|9,so that the inner firing contact 2|| is displaced by an amount dependingupon the speed of rotation of the magnet 2I9, which speed is a functionof the roll or pitch of the ship, so that outer firing contact 2I6engages inner contact 2|| at an earlier time. Copending applicationSerial No. 98,877, filed September 1, 1936, discloses further details ofconstruction of the firing delay compensators II5 and 2I0.

'Ihe electric follow-up and firing circuits are selected by a masterselector switch 225 (Fig. 1), having two positions marked Directorcorrection re and Cross-level fire. When this master switch is inposition for director correotion re of the guns, cross-level follow-up 4and director correction follow-up 96 are energized, whereas levelfollow-up 204 is deenergized.

Then the ring circuits to the guns are automatically completed at theproper time through the firing contacts 2| and 2| 6 of the directorcorrection ring device 2 I1.

When the master selector switch is in Crosslevel fire position, onlylevel fo1loW-up204 is energized, whereas cross-level follow-up 4 anddirector correction follow-up |96 are deenergized, and the firingcircuits to the guns are automatically completed at the proper timethrough the firing-contacts 22| and 222 of the cross-level firing deviceH6, the inner contact 22| of which is driven by firing delay compensatorI|5, and the outer contact 222 of which is driven by the differentialI|1 through shaft 223 and gear 224.

rl'he single follow-up motor 205, employed for both follow-ups 204 and|96 remains energized for both positions of 'the master switch, as inone position thereof follow-up |96 is energized, While in the otherposition, follow-up 204 is energized. Where manual follow-ups 39, |26,or 203 are employed, cut-out switches are'provided for the follow-upmotors which they substitute, namely, 36, |23 and 205, respectively.

Director correction fire is used when the m0- tion of the ship is in theplane of sight, or When level angle, as indicated on generated leveldial 20|, is greater than cross-level angle, as indicated on generatedcross-level dial I3. Crosslevel re is selected when the motion of theship is across the plane of sight, or When cross-level angle', asindicated on generated cross-level dial II3, is greater than levelangle, as indicated on generated level dial 20|.

In operation of the selective gun fire control.

system of this invention, With director correction fire selected, theroll and pitch converter 34 receives roll and pitch plus roll anglesrnechanically from stable element |0 by means of respective shafts 28and 29, and also receives relative target bearing by means of shaft 35,from follow-up 31, the motors 38 of Which receive it electrically fromthe controlling director. These inputs are combined in the roll andpitch converter in the manner described into level and cross-levelangles, which are transmitted by means of respective output shafts I|2and |08.

Cross-level angle is transmitted from shaft I 99 through follow-up II4,follow-up motor |23 and shafts |I8 and I 24 into trunnion-tilt correctorI25, Where it is combined with range elevation, introduced by hand-crank|29, gears |30 and shaft |3I, and with sight deflection, introduced byhand-crank |31, gears |38 and shaft I 39 to give corrected elevation(Ec) output by shaft |15 and corrected sight deflection (Ae) output byshaft |83.

Corrected elevation (Ec) is combined in mechanical differential |89 withthe director correction from shaft |90 to give the gun elevation order(Oe) which is transmitted to indicating dials |93 located at theinstrument, and also to electrical transmitter |94, from which it iselectrically transmitted to suitable receiving motors with dials orconventional automatic follow-up mechanism, not shown, located at thebattery, so that the position of the guns in elevation may becontinuously corrected in accordance with the gun elevation order (Oe).

Corrected sight deflection (Ac) is combined in electrical differentialtransmitters |84 With relative target bearing received electricallythrough connections from the controlling director to give gun trainorder (Ot) which is transmitted electrically to receiver motors |81operating in-V dicating dials |88 located at the instrument, and also toreceiving motors with indicating dials or automatic follow-up mechanism,not shown, 1o-

cated at the battery, so that the position of the gunsin train may becontinuously corrected in accordance with gun train order (Ot) The rolland pitch converter 34 transmits level to-dial to firing delaycompensator 2|0, and to mechanical differential 2|3, where it iscombined with the director correction angle from Ifollow-up |98 andshaft |91, its output shaft 2I4 being connected to gear 2l5 drivingouter contact `2| 6 of automatic firing device 2|1.

-rected for director correction, that is, with inner firing contact 2I|locked on zero, the contacts 2| I and 2|6 will engage, thus closing thegun ring circuit at the instant the ship is in a position correspondingto the director correction input. The inner Contact 2|| is carried byone member 220 of firing delay compensator 2 I 0, which causes the innercontact 2|I to be advanced an amount proportional to the ring delay andvaried automatically with' the speed of the ship in level motion. `Thusthe battery is iired automatically when contacts 2|| and 2| 6 engage, inaccordance ywith generated level, director correction and firing delaycompensation.

The roll and pitch converter 34 transmits the cross-level angle by meansof shaft |88 to dial I3, to ring delay compensator I I5, to one memberof mechanical differential II'I, and to followup II4. Through the latterand corresponding follow-up motorv |23, the second input member ofdiierential I|`| receives cross-level angle, so the resultant output ofdiierential |I1 is zero. Therefore, outer contact 222 of automatic ringdevice H6, driven by gear 224 on diierential output shaft 223, remainsstationary. Firing contacts 22| and 222 were cut out of the firingcircuit by the master selector switch when director correction fire wasselected.

With the master selector switch set in Cross level iire position,operation of, and inputs to, the roll and pitch converter 34 are thesame as for director correction re. Roll and pitch converter 34 thustransmits level angle to dial 20|, to iiring delay Compensator 2|0, toone side of differential 2|3, and to follow-up 294, which in turntransmits level to the other side of differential 2|3, so that itsresultant output to shaft 2|4 and gear 2l5 is zero. Outer contact 2|6 ofautomatic iiring device 2|`| accordingly remains stationary. Firingcontacts 2|I and 2|6 of auto- `matic firing device 2|'| were cut out ofthe firing circuit by the master selector switch when crosslevel firewas selected.

Follow-up 284 also transmits level angle to one side of differential |89which combines it with the corrected range elevation (Ec) receivedthrough shaft |75 from trunnion-tilt corrector |25, to give resultantgun elevation order (Oe), which `is transmitted mechanically to dials|93 located at the instrument, and also is transmitted electrically'bytransmitters |94 to receiving motors with dials or automatic follow-upmechanism, not shown, located at the battery, so the position of theguns in elevation may be continuously corrected in accordance with theelevation order (Oe) As before, the roll and pitch converter 34transmits cross-level angle to dial H3, to firing delay compensator ||5,and to one side of mechanical diierential H1, the output shaft 223 ofwhich drives through gear 224 outer contact 222 of automatic firingdevice H6. The othersideof differential receives a selected value ofcrosslevel as set in by hand crank |28 and indicated on cross-level setdial |22. This cross-level set is similar to setting of directorcorrection and is made by observing the concentric dials of the ringcontacts 22Iand 222 of iiring device I I5 to ascertain the maximumnumber of opportunities to re the gun battery. Outer contact 222 thusmoves in synchronism with motion f the ship in cross-level, correctedfor the selected cross level set at which the battery is to bered. Innercontact 22| is carried by tiring delay compensator H15, so that innercontact 22| is advanced by an angle which isproportional to the ringdelay and which is automatically varied in accordance With the speed ofthe ship in crosslevel motion. For automatic fire, thebattery is iredWhen contacts 22| and 222 engage.

Cross-level set from hand crank |28 vis transmitted by shafts I I8 and|24 to the trunnionetilt corrector |25. Follow-up motor |23 is not ener-'gized during cross-level ring so that follow-up I |4 is inoperative.

The corrected sight deection (lAc) from shaft |83 is combined, as in thecase of director Icorrection fire, with relativetarget bearing inelectrical diierentials |84 and is electrically transmitted to dials |88at the instrument, and also to receiving motors with dials or automaticfollow-up mechanism, not shown, located at the battery,'so the positionof` guns in train may be continuously corrected in accordance with thegun train order (Ot) It will be seen that a highly flexible selectivesystem of gun fire control is provided by this invention, whereby themain battery or other guns may be automatically red with a high andconsistent degree of accuracy at any selected position, irrespective ofthe ships motion in roll and pitch. l Y

While apreferred embodiment of the invention isv illustrated anddescribed herein, it is to be understood'thatthe invention lis notlimited thereby, but is susceptible of changes in form'and detail withinthe scope of the appended claims.

We claim:

1. In a system for controlling ship gun fire, the combination of stablemeans for determining the angle of unstable movement of theship, meansactuated in accordance With target bearing, mechanism jointly actuatedby said two means for converting said angle into level angle, meansresponsive vto the, trunnion-tilt displacement of the ship from thehorizontal about the lineoi sight to the target, mechanism actuated inaccordance with range elevation, operative connections between saidtrunnion-tilt means and said range elevation mechanism for modifying themovement of the latter, means for combining the output of said twomechanisms, and means actuated by said last-named means for indicatingcorrected elevation.

2. In a system for controlling ship gunfire, the combination of stablemeans for determining the angle of unstable movement of the'ship,`meansactuated in accordance with target bearing, mechanism jointlyactuated by said two means for converting said angle into cross-level nangle, means actuated by said mechanism `for determining "trunnion-tiltdisplacement of the ship from the horizontal'about the line of sight torthe target, means actuated in accordance with sight deection,operativeconnections between said trunnion-tilt means and said sightdeflection means for modifying the movement of the latter, and meansactuated by said lastnamed means for indicating corrected train.

3. In a system for controlling ship gun fire, the combination of stablemeans for determining the angle of unstable movement of the ship, meansactuated in accordance with target bearingmechanism jointly actuated bysaid two means for converting said angle into cross-level angle, meansactuated by said mechanism for determining trunnion-tilt displacement ofthe shipfrom the horizontal about the line of sight to the target, meansactuated in accordance with range elevation, operative connectionsbetween said trunnion-tilt means and said range elevation means formodifying the output of the latter, means actuated in accordance withdirector correction, means for combining the outputs of said rangeelevation means and said director correction means, and means actuatedby said last-named means for indicating corrected elevation. 4, In asystem for controlling ship gun re, the combination of stable means fordetermining the angle of unstable movement of the ship, means actuatedin accordance with target bearing, mechanism jointly actuated by saidtwo means for converting said angle into cross-level angle, meansactuatedby said mechanism for determining trunnion-tilt displacement ofthe ship from the horizontal about the line of sight to the target,means actuated in accordance with range elevation, operative connectionsbetween said trunnion-tilt means and said range elevation means formodifying the output of the latter, means for modifying'the output ofsaid range elevation means in accordance with a predetermined angularcorrection, and means actuated by the output of said range elevationmeans for indicating corrected elevation.

5. In a system for controlling ship gun re, the combination of stablemeans for determining the angle of unstable movement of the ship, meansactuated in accordance with target bearing, mechanism jointly actuatedby said two means for converting said angle into level and cross-levelangles, means actuated by said mechanism for determining trunnion-tiltdisplacement of the ship from the horizontal about the line of sight tothe target, means actuated in accordance with sight deflection,operative connection between said trunnion-tilt means and said sightdeflection means for modifying the output of the latter, means forcombining the output of the last-named means with the output of saidtarget bearing means, and means actuated by said last-named means forindicating corrected sight deflection.

6. In a system for controlling ship gun iire, the combination of stablemeans for determining the angle of unstable movement of the ship, meansactuated in accordance with target bearing, mechanism jointly actuatedby said two means for converting said angle into level and cross-levelangles, means actuated by said mechanism for determining trunnion-tiltdisplacement of the ship from the horizontal about the line of sight tothe target, means actuated in accordance with sight deflection,operative connections between said trunnion-tilt means and said sightdeflection means for modifying the output of the latter, means forcombining the output of the last-named means with the output of saidtarget bearing means, means actuated `12 in accordance with rangeelevation, operative connections between said trunnion-tilt means andsaid range elevation means for modifying the output of the latter, meansfor modifying the output of said range elevation means in accordancewith' a predetermined angular correction,

`means actuated by the output of said range elevation means forindicating corrected elevation, and means actuated by said combiningmeans for indicating corrected sight deilection.

'7. In a system for controlling ship gun fire, the combination of stablemeans for determiningthe `angle of unstable movement of the ship, meansactuated in accordance with target bearing, mechanism jointly actuatedby said two means for converting said angle into cross-level angle,electrical contacts for firing the gun upon engagement, and meansactuated by said mechanism nfor effecting engagement of said contacts.

8. In a system for'controlling ship gun re, the combination of stablemeans for determining the angle of unstable movement of the ship, meansactuated in accordance with target bearing, mechanism jointly actuatedby said two means forconverting said angle into level angle, electricalcontacts for ring the gun upon engagement, means actuated by saidmechanism for eiecting engagement of said contacts, and means formodifying theA actuation of said lastnamed means in accordance withdirector correction.

9. In a system for controlling ship gun fire, the combination of stablemeans for determining the angle of unstable movement of the ship, meansactuated in accordance with target bearing, mechanism jointly actuatedby said two means for converting said angle into level angle, electricalcontacts for iiring the gun upon engagement, means actuated by saidmechanism yfor effecting engagement of said contacts, and means formodifying the actuation of said lastnamed means in accordance with apredetermined angular correction.

10. In a system for controlling ship gun re, the combination of stablemeans for determining the angle of unstable movement of the ship, meansactuated in accordance with target bearing, mechanism jointly actuatedby said two means for converting said angle into cro-ss-level angle,electrical contacts for ring the gun upon engagement, means actuated bysaid mechanism for effecting engagement of said contacts, and manualmeans for modifying the actuation of said last-named means in accordancewith crosslevel set.

11. In a system for controlling ship gun iire, the combination of stablemeans for determining the angle of unstable movement of the ship, meansactuated in accordance with target bearing, mechanism jointly actuatedby said two means for converting said angle into level angle, mechanismjointly actuated by said two means for converting said ship angle intocross-level angle, two sets of electrical contacts for alternativelyfiring said gun upon engagement, operative connections between one setof said firing contacts and said level angle mechanism, operativeconnections between said otherset of contacts and said cross-levelmechanism, and selective means controlling said connections forrendering either of said contacts operative to re the gun.

y12. In a system for controlling ship gun fire, the combination ofstable means for determining the angle of unstable movement of the ship,

means actuated in accordance with target bearing, mechanism jointlyactuated by said two means for converting said angle into level angle,mechanism jointly actuated by said two means for converting said shipangle into cross-level angle, two sets of electrical contacts foralterl:natively iiring said gun upon engagement, operative connectionsbetween one set of said ring contacts and said level angle mechanism,operative connections between said other set of contacts and saidcross-level mechanism, selective means controlling said connections forrendering either` of said contacts operative to iire the gun, and meansfor modifying the level connections to said corresponding contacts inaccordance with director correction.

13. In a system for controlling ship gun re, the combination of stablemeans for determining the angle of unstable movement of the ship, meansactuated in accordance with target bearing, mechanism jointly actuatedby said two means for converting said angle into level angle, mechanismjointly actuated by said two means for converting said ship angle intocross-level angle, two sets of electrical contacts for alter- 'nativelyiiring said gun upon engagement, operative connections between one setof said ring contacts and said level angle mechanism, operativeconnections between said other set of contacts and said cross-levelmechanism, selective means controlling said connections for renderingeither of said contacts operative to re the gun, and means for modifyingthe cross-level connections to said corresponding contacts in accordancewith a predetermined angular correction.

14. In a system for controlling ship gun re, the combination of stablemeans for determining the angle of unstable movement of the ship, meansactuated in accordance with target bearing, mechanism jointly actuatedby said two means for converting said angle into level angle, mechanismjointly actuated by said two means for converting said ship angle intocross-level angle, two sets of electrical contacts for alternativelyring said gun upon engagement, operative connections between one set ofsaid firing contacts and said level angle mechanism, operativeconnections between said other set of contacts and said cross-levelmechanism, selective means controlling said connections for renderingeither of said contacts operative to fire the gun, and means formodifying the level connections to said corresponding contacts inaccordance with a predetermined angular correction.

15. In a system for controlling ship gun fire, the combination of stablemeans for determining the angle of unstable movement of the ship, meansactuated in accordance with target bearing, mechanism jointly actuatedby said two means for converting said ship angle into crosslevel angle,means actuated in accordance with range elevation, means jointlyactuated by said mechanism and range elevation means in accordance withthe hereinbefore dened factor E cos CL-d sin CL and means for indicatingthe output of said last means as corrected range elevation.

16. In a system for controlling ship gun fire, the combination of stablemeans for determining the angle of unstable movement of the ship, meansactuated in accordance with target bearing, mechanism jointly actuatedby said two means for converting said ship angle into crosslevel angle,means actuated in accordance with sight deflection, means jointlyactuated by said mechanism and sight deilection means in accordance withthe hereinbefore-deiined factor E sin CL-i-d cos CL and means forindicating the output of said lastnained means as corrected sightdeflection.

17. In a system for controlling ship gun fire, the combination of stablemeans for determining the angle of unstable movement of the ship, meansfor indicating said angle of unstable movement, means actuated inaccordance with target bearing, mechanism jointly actuated by saidstable means and said target bearing actuated means for converting saidangle of unstable movement into level angle, and means actuated by saidmechanism for indicating the said level angle existing simultaneouslywith the said indicated unstable movement angle.

18. In a system for controlling ship gun re,

the combination of stable means for determining the angle of unstablemovement of the ship, meansfor indicating said angle of unstablemovement, means actuated in accordance with target bearing, mechanismjointly actuated by said stable means and said target bearing actuatedmeans for converting said angle of unstable movement into cross-levelangle, and means actuated by said mechanism for indicating the saidcross-level angle existing simultaneously with the said unstablemovement angle.

19. In a system for controlling ship-gun lire, the combination of stablemeans for determining the angles of pitch and roll of the ship, meansfor indicating said angles of pitch and roll, means actuated inaccordance with target bearing, mechanism jointly actuated by saidstable means and said target bearing actuated means for converting saidangles of pitch and roll into level and cross-level angles, and meansactuated by said mechanism for indicating the said level and cross-levelangles existing simultaneously withv the said angles of pitch and roll.

20. In a system for controlling ship gun lire, the combination of stablemeans for determining the angle of unstable movement of the ship, meansfor indicating said angle of unstable movement, means actuated inaccordance with target bearing, mechanism jointly actuated by saidstable

